Then the doctor examines him and perhaps performs some laboratory or other tests.

Finally, having arrived at a diagnosis, the doctor applies the correct treatment, be it pharmacological or surgical.

From the purely abstract point of view, it is all rather simple and straightforward.

In practice, however, complications sometimes arise.

For example, last week there was a patient in my ward who told me that he had been off sick from work for the past year.

‘With what sickness?’ I asked.

Normally in these circumstances this question produces puzzlement, as if it were a complete irrelevance. But this particular patient was well prepared.

‘Backache,’ he said. ‘I’ve got severe pain in my back.’

I confess I was surprised.

He looked a fit young man to me, and he moved around with perfect ease, not like a man crippled by back pain.

Moreover, he had a number of cuts and bruises on him, the result of having been beaten up by a gang of children who had tried to mug him in the street and whom he had unwisely chased.

People with back pain are quite often mugged, of course, but they rarely run after their muggers.

Perhaps this man was emboldened by the fact that his hobby was martial arts: again, an odd choice of pastime for someone with incapacitating backache.

I telephoned his general practitioner with my suspicions, thinking that perhaps he had been deceived by his patient into signing him off sick.

I told the doctor my grounds for suspecting that his patient’s backache was not as bad as he claimed. It turned out, however, that I was telling the doctor nothing he did not already know.

‘Yes,’ he said, ‘he has never struck me as having been in much pain.’

‘But he has been off sick for the past year,’ I said, my voice tinged with outrage.

‘Yes,’ said the doctor, ‘but the last patient whom I made fit to work when he didn’t want to return to work picked up my computer and threw it at me. We ended up having a fight on the floor.’

I understood at once.

It isn’t only sick notes that are procured by threat, of course: round here all mind-altering substances – tranquillisers and antidepressants – are prescribed not for the patient’s sake but to forestall an attack on the doctor, who gives that patient whatever he wants to remove him from his presence as quickly as possible, before the patient spits at or punches him.

Things are a little better in the prison, I’m glad to say.

There the doctor is free to do what he thinks is best for the patient, thanks to the proximity of several very large men at his beck and call.

Last week, a patient arrived in the prison, a fit (though presumably not very skilful) young burglar.

‘Are you on any treatment?’ I asked him.

‘Yes,’ he said. ‘DF 118, diazzies and amitrippiline.’

An opiate analgesic, an addictive tranquilliser (diazepam) and an antidepressant (amitriptyline).

‘Why?’ I asked.

‘Backache,’ he replied.

‘Ah, a burglar with a backache.’ I said.

He smiled at me, and I smiled back.

Then we had a good chuckle together.

I knew, he knew I knew, I knew he knew I knew, and he knew I knew he knew I knew.

‘Nice one, Doctor,’ he said as he left the room, in excellent spirits.

British slang converter:

‘Sick notes’ – notes provided by a doctor to a patient excusing the patient from work and enabling him to claim statutory sick pay or other benefits.

For loving someone ‘to bits’ in modern British parlance connotes regular strangulation, either given or received. I leave it to marriage guidance counsellors to decide whether, in this context, it is more blessed to give or to receive.

Of course, the words ‘on my baby’s life’ are also pretty terrible, irresistibly conjuring up as they do images of Old Testament sacrifice; but, in fact, ‘on my baby’s life’ means only that everything that follows is an unadulterated lie.

Thus ‘On my baby’s life, doctor, I never touched her’ means ‘I beat her unconscious regularly and broke several bones in her body’.

It is also a fact that men who say ‘on my baby’s life’ always abandon their children in the end.

A man who both loved his girlfriend to bits and swore on his baby’s life that he hadn’t laid a finger on her took an overdose because she had left him. It seemed that he had smashed up the flat in which they lived and which he had just redecorated.

‘Every time I try to do something, doctor,’ he said, ‘it just explodes at me.’

‘And would you take another overdose, then?’ I asked.

‘Sod that, man,’ he said. ‘It’s caused too much pain in my head.’

He was a strangler, of course, though only an amateur by comparison with some I have met. In any case, a true strangler needs his strangulee, for as everyone knows it takes two to strangle. And, as it happens, there was a classic strangulee in the next bed.

She, too, had tried to kill herself with pills because she had had enough. The problem was that the strangler in her life kept telephoning, and each time she weakened and let him back into her house.

‘When he’s not strangling me,’ she said, ‘he’s very nice.’

‘How did you meet him?’ I asked.

‘In a pub.’

‘And how long had you known him before he moved in with you?’

‘A few hours.’

‘Has he a criminal record?’

‘Yes.’

‘Has he been to prison?’

‘Yes.’

‘What for?’

‘He was in eight years for murder. He ran over someone with his lorry.’

‘If I’ve understood you correctly, you met a murderer in a pub, you started to live with him a few hours later, and he has repeatedly half-strangled you.’

‘Yes, doctor.’

‘I hope you don’t mind me asking, but why do you stay with him?’

‘I love him to bits, doctor.’

I howled. I laughed. I wanted to bang my head on the wall and climb straight to the hospital roof and throw myself off. In the event, I merely clutched my head. She started to laugh.